Question

The width of a rectangle is 15 cm less than 3 times the length. if the area is 42 square cm. find the dimensions of the rectangle.

Answer 1

It's the right ANSWER

Answer 2

The dimensions of the rectangle are 7 cm by 6 cm.

Step-by-step explanation:

The 15 cm less than 3 times the length is the width of the rectangle.

So, if the length = L cm and the width = W will be given by

W = 3L - 15 ........ (1)

Now, it is given that 42 sq. cm. is the area of the rectangle.

So, LW = 42

⇒ L(3L - 15) = 42 {From equation (1)}

⇒ 3L² - 15L - 42 = 0

⇒ L² - 5L - 14 = 0

⇒ (L - 7)(L + 2) = 0

So, L = 7 cm or L = - 2 cm

But L can not be negative, so L = 7 cm.

Now, WL = 42

⇒ W = 6 cm.

Therefore, the dimensions of the rectangle are 7 cm by 6 cm. (Answer)